/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

package org.apache.tomcat.jni;

import java.nio.ByteBuffer;

/**
 * Buffer
 *
 * @author Mladen Turk
 */
public class Buffer {

	/**
	 * Allocate a new ByteBuffer from memory
	 *
	 * @param size The amount of memory to allocate
	 * @return The ByteBuffer with allocated memory
	 */
	public static native ByteBuffer malloc(int size);

	/**
	 * Allocate a new ByteBuffer from memory and set all of the memory to 0
	 *
	 * @param num  Number of elements.
	 * @param size Length in bytes of each element.
	 * @return The ByteBuffer with allocated memory
	 */
	public static native ByteBuffer calloc(int num, int size);

	/**
	 * Allocate a new ByteBuffer from a pool
	 *
	 * @param p    The pool to allocate from
	 * @param size The amount of memory to allocate
	 * @return The ByteBuffer with allocated memory
	 */
	public static native ByteBuffer palloc(long p, int size);

	/**
	 * Allocate a new ByteBuffer from a pool and set all of the memory to 0
	 *
	 * @param p    The pool to allocate from
	 * @param size The amount of memory to allocate
	 * @return The ByteBuffer with allocated memory
	 */
	public static native ByteBuffer pcalloc(long p, int size);

	/**
	 * Allocate a new ByteBuffer from already allocated memory.
	 * <br>Allocated memory must be provided from call to the
	 * Stdlib.alloc or Stdlib.calloc methods.
	 *
	 * @param mem  The memory to use
	 * @param size The amount of memory to use
	 * @return The ByteBuffer with attached memory
	 */
	public static native ByteBuffer create(long mem, int size);

	/**
	 * Deallocates or frees a memory block used by ByteBuffer
	 * <br><b>Warning :</b> Call this method only on ByteBuffers
	 * that were created by calling Buffer.alloc or Buffer.calloc.
	 *
	 * @param buf Previously allocated ByteBuffer to be freed.
	 */
	public static native void free(ByteBuffer buf);

	/**
	 * Returns the memory address of the ByteBuffer.
	 *
	 * @param buf Previously allocated ByteBuffer.
	 */
	public static native long address(ByteBuffer buf);

	/**
	 * Returns the allocated memory size of the ByteBuffer.
	 *
	 * @param buf Previously allocated ByteBuffer.
	 */
	public static native long size(ByteBuffer buf);

}
